Newcastle lord mayor and developer Jeff McCloy has revealed his company donated almost $10,000 to a Liberal candidate before the 2011 election.

Political donations from property developers, tobacco or gaming interests are banned in New South Wales.

However Cr McCloy, who worked as property developer running his own construction company, wants to keep making political donations despite having been interviewed by the anti-corruption commission over the payments.

The revelations are contained in his High Court challenge to the law banning developer donations, lodged in the lead up to next week's hearings into illegal donations to the Liberal party.

Cr McCloy's writ against the State Government and the Independent Commission Against Corruption (ICAC) argues the ban is unlawful and therefore there was no act of corruption, because his company did nothing illegal.

If the High Court agrees to strike down the ban, it may have some impact on the ICAC investigation into the Liberal party's funding of the 2011 election campaign for the seat of Newcastle.

Hearings resume on Wednesday when ICAC will also examine two bitter campaigns against the former Labor MP for Newcastle, Jodi McKay.

One involved disgraced Labor MP Joe Tripodi, the other involved developers including Cr McCloy and the Newcastle company Buildev owned by Nathan Tinkler.

Greens MP John Kaye says a successful court challenge could undermine a large amount of the ICAC investigation.

"These are important hearings, they are public interest matters. They are about cleaning up politics in New South Wales," he said.

Cr McCloy's writ reveals that his company made a gift of $9,975 for what it calls "the benefit of persons including a candidate connected to the 2011 state election".

It says he is now aware the gift recipient was a member of the staff of Newcastle Liberal candidate, Tim Owen.

Earlier revelations about the developer donations lead to Mr Owen deciding in May not to recontest the seat he wrested from the Labor Party in the state election.

Cr McCloy's court claim uses the argument that developer donations are a form of political freedom.

The implied freedom of communication on government and politics in the constitution was cited by Unions New South Wales in its successful challenge to a ban on union donations to political parties.

Mr Kaye says that win was partially because the corrupting influence of unions was not demonstrated.

"I hope the Coalition Government defends the case by demonstrating the corrupting influence of developer donations on state politics," he said.

"If Cr McCloy's writ succeeds, it will certainly take New South Wales backwards in the battle against corruption."